I don't think I had a militant attitude, but I do think saying, "I don't understand..." rather than "I disagree with..." puts a sour note on the entire conversation.
You literally went to their profile and called them out about how they should be able to understand something you’re describing as so easy to understand.
Yeah, what is the problem with that? They engaged dishonestly by claiming they didn't understand something, why should I do anything other than call them on that?
OK — just don’t be surprised when people think you’re being a jerk because you didn’t like the words someone chose. I’d assert you’re acting in bad faith more than the person you responded to.